From db6ccbb61c1291c8aaefadcc8304444f27eeb88d Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 6 Jan 2007 22:53:48 +0000 Subject: [PATCH] [ARM] Fix kernel-mode undefined instruction aborts If the kernel attempts to execute a CP1 or CP2 instruction and it aborts, and a FP emulator is not loaded, we try to return as if to a user context, instead of the proper kernel context. Since the fault came from kernel mode, we must use the kernel return paths. Signed-off-by: Russell King --- arch/arm/kernel/entry-armv.S | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 2db42b18f5..8517c3c3eb 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -436,7 +436,7 @@ __und_usr: usr_entry tst r3, #PSR_T_BIT @ Thumb mode? - bne fpundefinstr @ ignore FP + bne __und_usr_unknown @ ignore FP sub r4, r2, #4 @ @@ -448,7 +448,7 @@ __und_usr: @ 1: ldrt r0, [r4] adr r9, ret_from_exception - adr lr, fpundefinstr + adr lr, __und_usr_unknown @ @ fallthrough to call_fpe @ @@ -476,7 +476,9 @@ __und_usr: * Emulators may wish to make use of the following registers: * r0 = instruction opcode. * r2 = PC+4 + * r9 = normal "successful" return address * r10 = this threads thread_info structure. + * lr = unrecognised instruction return address */ call_fpe: tst r0, #0x08000000 @ only CDP/CPRT/LDC/STC have bit 27 @@ -545,10 +547,12 @@ do_fpe: .data ENTRY(fp_enter) - .word fpundefinstr + .word no_fp .text -fpundefinstr: +no_fp: mov pc, lr + +__und_usr_unknown: mov r0, sp adr lr, ret_from_exception b do_undefinstr -- 2.39.5